Throughput of the new GMOS-N R400 grating

Throughput measurements in preparation for the switchover to the new GMOS-N R400 grating on August 1st, 2025 (HST) confirm an improved throughput of the new grating compared to the current GMOS-N R400 grating.

The throughput measurements were obtained from consecutive observations of the same spectrophotometric standard star using both gratings. Further details on the definition of throughput for the GMOS spectroscopic throughput monitoring can be found on the GMOS performance monitoring webpages.